This subproject has the broad, long-term objectives of increasing scientific understanding of the prevalence, nature, scope, and development of chronic pain as a secondary condition in children and adults with disabilities. In this subproject, the investigators propose two studies to expand our understanding of pain in persons with disabilities. Study 1 is a survey of 3,730 adults and children with disabilities, and has three specific aims: (1) to extend our understanding of pain as a secondary condition in persons with disabilities to six populations not studied in the first funding cycle of the program project (that is, to adults with multiple sclerosis, neuromuscular disease, and post-polio syndrome, and 10 to 20-year-old children with spinal cord injury, limb deficiency, and cerebral palsy); (2) to further test and refine a biopsychosocial model of chronic pain in persons with disabilities by testing hypothesized concurrent associations between biopsychosocial predictors, pain, and functioning in the study participants; and (3) to better understand the severity of pain problems in persons with disabilities by comparing the average pain severity scores of persons in nine disability groups (adults with spinal cord injury, amputation, and cerebral palsy and the six new populations listed above) with each other and with national norms of these pain severity measures. Study 2 is a prospective, longitudinal survey study with two specific aims: (1) to perform prospective tests of hypothesized associations between biological and psychosocial variables and psychological functioning, pain interference with activities and participation across all disability groups studied; and (2) to better understand the natural course of pain over time in persons with disabilities. The findings from this subproject should contribute significantly to our understanding of pain as a secondary condition in adults and children with disabilities, and can also be used to identify promising pain interventions that should be examined further in prospective, controlled treatment trials. The participants recruited for this subproject will also contribute to our growing database of persons with disabilities, a database that will be used throughout the funding period to facilitate the recruitment of subjects for the other subprojects. Finally, the continued development of a large database of persons with disabilities creates the possibility of performing very long term studies of the development, course, and treatment of chronic pain problems over the life span of persons with disabilities.